वागेवर्क्प्राणः सामोमित्येतदक्षरमुद्गीथः । तद्वा एतन्मिथुनं यद्वाक्च प्राणश्चर्क्च साम च ॥ १.१.५ ॥
vāgevarkprāṇaḥ sāmomityetadakṣaramudgīthaḥ | tadvā etanmithunaṃ yadvākca prāṇaścarkca sāma ca || 1.1.5 ||
5. [In answer to the foregoing question:] Speech is the same as Ṛk; prāṇa [life] is the same as Sāma; and Om is nothing but udgītha [Brahman] itself. They are pairs: speech and life, Ṛk and Sāma.
Vāk eva ṛk, speech is Ṛk [being the cause of the Ṛk]; prāṇaḥ sāma, prāṇa [breath, or the life force] is Sāma [for you can sing the Sāma if your prāṇa is strong]; om iti etat akṣaram udgīthaḥ, the syllable ‘Om’ is the udgītha [for you recite it out of love for the Sāma]; tat etat vai mithunam, it is like a couple; yat vāk ca prāṇaḥ ca ṛk ca sāma ca, which are speech and prāṇa, Ṛk and Sāma.
The word ‘couple,’ or ‘pair,’ is being used to suggest a relationship of cause and effect. Cause and effect are, in fact, one and the same. Speech is the cause,
According to this Upaniṣad, the evolution of the gross world is in this order: earth, water, plants, human beings, speech, Ṛk, Sāma, and udgītha (Om). Udgītha is rasatamā, the essence of all essences, the cause of all causes. It occupies the eighth position—that is, it is the ultimate in the evolution of things. It is the Paramātman, the Self of all selves.